Correlation of current–voltage–temperature analysis with deep level defects in epitaxial GaN films

The effect of temperature on the nature of metal-semiconductor system in a Au contact deposited on c-plane and a-plane GaN film was investigated by current–voltage (I–V) measurements. The I–V measurements have been obtained systematically at different temperatures ranging from room temperature (300 K) to low temperature (78 K). Photoluminescence measurements were obtained to investigate correlation between the growth conditions, the substrate used for the growth of GaN film, and the presence of deep level defects therein by equating with the yellow band luminescence. The resistance–voltage–temperature analysis indicates that a gradual shift of the nature of contact towards Schottky behavior takes place while moving from room temperature to low temperature. Additionally, memory effect like aberration is present at low temperature, which can be attributed to the presence of deep-level defects and carrier recombination therein.